| # SPDX-License-Identifier: GPL-2.0+ |
| # |
| # Copyright (C) 2013, Miao Yan <miao.yan@windriver.com> |
| # Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com> |
| |
| VxWorks Support |
| =============== |
| |
| This document describes the information about U-Boot loading VxWorks kernel. |
| |
| Status |
| ------ |
| U-Boot supports loading VxWorks kernels via 'bootvx' and 'bootm' commands. |
| For booting old kernels (6.9.x) on PowerPC and ARM, and all kernel versions |
| on other architectures, 'bootvx' shall be used. For booting VxWorks 7 kernels |
| on PowerPC and ARM, 'bootm' shall be used. |
| |
| VxWorks 7 on PowerPC and ARM |
| --------------------------- |
| From VxWorks 7, VxWorks starts adopting device tree as its hardware decription |
| mechansim (for PowerPC and ARM), thus requiring boot interface changes. |
| This section will describe the new interface. |
| |
| For PowerPC, the calling convention of the new VxWorks entry point conforms to |
| the ePAPR standard, which is shown below (see ePAPR for more details): |
| |
| void (*kernel_entry)(fdt_addr, 0, 0, EPAPR_MAGIC, boot_IMA, 0, 0) |
| |
| For ARM, the calling convention is shown below: |
| |
| void (*kernel_entry)(void *fdt_addr) |
| |
| When booting a VxWorks 7 kernel (uImage format), the parameters passed to bootm |
| is like below: |
| |
| bootm <kernel image address> - <device tree address> |
| |
| VxWorks bootline |
| ---------------- |
| When using 'bootvx', the kernel bootline must be prepared by U-Boot at a |
| board-specific address before loading VxWorks. U-Boot supplies its address |
| via "bootaddr" environment variable. To check where the bootline should be |
| for a specific board, go to the VxWorks BSP for that board, and look for a |
| parameter called BOOT_LINE_ADRS. Assign its value to "bootaddr". A typical |
| value for "bootaddr" on an x86 board is 0x101200. |
| |
| If a "bootargs" variable is defined, its content will be copied to the memory |
| location pointed by "bootaddr" as the kernel bootline. If "bootargs" is not |
| there, command 'bootvx' can construct a valid bootline using the following |
| environments variables: bootdev, bootfile, ipaddr, netmask, serverip, |
| gatewayip, hostname, othbootargs. |
| |
| When using 'bootm', just define "bootargs" in the environment and U-Boot will |
| handle bootline fix up for the kernel dtb automatically. |
| |
| Serial console |
| -------------- |
| It's very common that VxWorks BSPs configure a different baud rate for the |
| serial console from what is being used by U-Boot. For example, VxWorks tends |
| to use 9600 as the default baud rate on all x86 BSPs while U-Boot uses 115200. |
| Please configure both U-Boot and VxWorks to use the same baud rate, or it may |
| look like VxWorks hangs somewhere as nothing outputs on the serial console. |
| |
| x86-specific information |
| ------------------------ |
| Before loading an x86 kernel, one additional environment variable need to be |
| provided. This is "vx_phys_mem_base", which represent the physical memory |
| base address of VxWorks. |
| |
| Check VxWorks kernel configuration to look for LOCAL_MEM_LOCAL_ADRS. For |
| VxWorks 7, this is normally a virtual address and you need find out its |
| corresponding physical address and assign its value to "vx_phys_mem_base". |
| |
| For boards on which ACPI is not supported by U-Boot yet, VxWorks kernel must |
| be configured to use MP table and virtual wire interrupt mode. This requires |
| INCLUDE_MPTABLE_BOOT_OP and INCLUDE_VIRTUAL_WIRE_MODE to be included in a |
| VxWorks kernel configuration. |
| |
| Both 32-bit x86 and 64-bit x64 kernels can be loaded. |
| |
| There are two types of graphics console drivers in VxWorks. One is the 80x25 |
| VGA text mode driver. The other one is the EFI console bitmapped graphics mode |
| driver. To make these drivers function, U-Boot needs to load and run the VGA |
| BIOS of the graphics card first. |
| |
| - If the kernel is configured with 80x25 VGA text mode driver, |
| CONFIG_FRAMEBUFFER_SET_VESA_MODE must be unset in U-Boot. |
| - If the kernel is configured with bitmapped graphics mode driver, |
| CONFIG_FRAMEBUFFER_SET_VESA_MODE need remain set but care must be taken |
| at which VESA mode is to be set. The supported pixel format is 32-bit |
| RGBA, hence the available VESA mode can only be one of the following: |
| * FRAMEBUFFER_VESA_MODE_10F |
| * FRAMEBUFFER_VESA_MODE_112 |
| * FRAMEBUFFER_VESA_MODE_115 |
| * FRAMEBUFFER_VESA_MODE_118 |
| * FRAMEBUFFER_VESA_MODE_11B |